Liquid vacuum trucks are used to collect and transport hazardous and non-hazardous liquid and semi-liquid waste. Non-hazardous waste includes sewage and septic materials. Hazardous waste, waste that poses a substantial threat to public health or the environment, includes volatile organic compounds, nitrogen oxide, sulfur dioxide, and other particulate waste matter. Liquid vacuum trucks are also frequently used to assist in cleaning up waste spills and for transporting liquids and semi-solids at industrial facilities.